markers-userspace/marker-lib.c

   1
   2 #include "marker.h"
   3 #include <stdio.h>
   4 #include <errno.h>
   5
   6 __attribute__ ((visibility ("protected")))
   7 extern struct marker __start___markers[];
   8
   9 __attribute__ ((visibility ("protected")))
  10 extern struct marker __stop___markers[];
  11
  12 /**
  13  * __mark_empty_function - Empty probe callback
  14  * @probe_private: probe private data
  15  * @call_private: call site private data
  16  * @fmt: format string
  17  * @...: variable argument list
  18  *
  19  * Empty callback provided as a probe to the markers. By providing this to a
  20  * disabled marker, we make sure the  execution flow is always valid even
  21  * though the function pointer change and the marker enabling are two distinct
  22  * operations that modifies the execution flow of preemptible code.
  23  */
  24 __attribute__ ((visibility ("protected")))
  25 void __mark_empty_function(void *probe_private, void *call_private,
  26         const char *fmt, va_list *args)
  27 {
  28 }
  29
  30 /*
  31  * marker_probe_cb Callback that prepares the variable argument list for probes.
  32  * @mdata: pointer of type struct marker
  33  * @call_private: caller site private data
  34  * @fmt: format string
  35  * @...:  Variable argument list.
  36  *
  37  */
  38 __attribute__ ((visibility ("protected")))
  39 void marker_probe_cb(const struct marker *mdata, void *call_private,
  40         const char *fmt, ...)
  41 {
  42         static unsigned int count = 0;
  43
  44         printf("Test probe function %u\n", count++);
  45 }
  46
  47 //FIXME : imv_read won't work with optimized immediate values.
  48 //will need to issue one sys_marker call for each immediate value.
  49 __attribute__ ((visibility ("protected")))
  50 void testip(void)
  51 {
  52         printf("addr : %p\n", __builtin_return_address(0));
  53 }
  54
  55 __attribute__((constructor, visibility ("protected")))
  56 void marker_init(void)
  57 {
  58         struct marker *iter;
  59         int ret;
  60
  61         printf("Marker section : from %p to %p (init)\n",
  62                 __start___markers, __stop___markers);
  63         testip();
  64         for (iter = __start___markers; iter < __stop___markers; iter++) {
  65                 printf("Marker : %s\n", iter->name);
  66                 ret = sys_marker(iter->name, iter->format,
  67                         &imv_read(iter->state), 1);
  68                 if (ret)
  69                         perror("Error connecting markers");
  70         }
  71 }
  72
  73 __attribute__((destructor, visibility ("protected")))
  74 void marker_fini(void)
  75 {
  76         struct marker *iter;
  77         int ret;
  78
  79         printf("Marker section : from %p to %p (fini)\n",
  80                 __start___markers, __stop___markers);
  81         for (iter = __start___markers; iter < __stop___markers; iter++) {
  82                 printf("Marker : %s\n", iter->name);
  83                 ret = sys_marker(iter->name, iter->format,
  84                         &imv_read(iter->state), 0);
  85                 if (ret)
  86                         perror("Error disconnecting markers");
  87         }
  88 }